1. Technical Field of the Invention
This invention relates generally to HVAC (heating, ventilation, and air conditioning) systems, and more specifically to a valve manifold mechanism for operating duct airflow control bladders.
2. Background Art
FIG. 1 is a block diagram of a typical forced air system. The existing central HVAC unit 10 is typically comprised of a return air plenum 11, a blower 12, a furnace 13, an optional heat exchanger for air conditioning 14, and a conditioned air plenum 15. The configuration shown is called “down flow” because the air flows down. Other possible configurations include “up flow” and “horizontal flow”. A network of air duct trunks 16 and air duct branches 17 connect from the conditioned air plenum 15 to each air vent 18 in room A, room B, and room C. Each air vent is covered by an air grill 31. Although only three rooms are represented in FIG. 1, the invention is designed for larger houses with many rooms and at least one air vent in each room. The conditioned air forced into each room is typically returned to the central HVAC unit 10 through one or more common return air vents 19 located in central areas. Air flows through the air return duct 20 into the return plenum 11.
The existing thermostat 21 is connected by a multi-conductor cable 73 to the existing HVAC controller 22 that switches power to the blower, furnace and air conditioner. The existing thermostat 21 commands the blower and furnace or blower and air conditioner to provide conditioned air to cause the temperature at thermostat to move toward the temperature set at the existing thermostat 21.
FIG. 1 is only representative of many possible configurations of forced air HVAC systems found in existing houses. For example, the air conditioner can be replaced by a heat pump that can provide both heating and cooling, eliminating the furnace. In some climates, a heat pump is used in combination with a furnace. The present invention can accommodate the different configurations found in most existing houses.
Pneumatic and hydraulic valve systems are well known in a variety of industries. Most valve systems comprise only a single valve which is actuated to control the flow of a single fluid under pressure or vacuum. Most valve systems are, essentially, binary switches, such as a pneumatic valve which selectively fully couples or fully decouples a tire inflation chuck from an air pressure source such as a pressurized tank. Other valve systems provide a more analog control, such as a hydraulic control valve which enables a heavy equipment operator to provide a variety of pressures or flows of hydraulic fluid from a (single pressure) high pressure supply pump to a hydraulic ram actuating an articulating bucket or other such component. Still other valve systems include a battery of plural valves, each controlling the flow of a respective individual fluid, such as a multi-beverage fountain dispenser from which a consumer can retrieve any of a variety of soft drinks from respective ones of a variety of nozzles. In this latter instance, the individual valves not only control the flow of their respective soft drink syrups, but they are each also coupled to a common carbonated water supply.
What is not available, however, is a valve manifold which enables individual valves to be operated to each independently select between two or more fluid flows.